I realize this still does not answer your main question, but your updated code probably does not do what you want:
unless(@allowedext = $extension)
That is an assignment, whereas you probably wanted some kind of comparison. You clobber all elements of the array, then set the array to a single value. Since the assignment is (probably) always successful, you never enter the unless clause. I think you really want a hash like GrandFather suggested.

In reply to Re: extension check on upload script doesn't do anything by toolic
in thread extension check on upload script doesn't do anything by edwardra3

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